A Natural end (n.) is a causality we borrow all the time from ourselves and attribute to other beings, without meaning to assume they are made like us.
A Natural end (n.) is a thing that is both cause and effect of itself.
A Natural end (n.) is not a constitutive concept but a regulative one: a guide for investigating living things by remote analogy with our own purposes.
A Natural end (n.) as a concept is a stranger in natural science, tempting us to drop our study of nature and follow it beyond nature.
A Natural end (n.) as a concept cannot be judged dogmatically: we do not know whether we are judging about something or nothing.
A Natural end (n.) is a thing whose inner possibility presupposes a purpose — a concept that must condition the causality of its own production.